Friday, February 26, 2010

We’ve got a little stereo in our kitchen that keeps us entertained when we’re cooking. It’s getting on a bit, though: it doesn’t always read CDs, songs begin skipping at the most inopportune moments and the speakers occasionally fail, requiring Fonzie-esque thumbs to reignite. While the latter undeniably draws respect from your male friends and makes the ladies swoon, having Mick Jagger develop the most irritating and incurable stutter when you’re busy straining pasta or removing hot dishes from the oven is starting to get a little irritating. Hence, last weekend, I went shopping for a replacement. While the internet is undeniably the place to buy things cheaply, there’s still something to be said for looking at your intended purchases in person and taking the demonstration models for a test drive. Problem is, the same time that you’re swayed by the bass levels, swish CD-loading motion and flashing lights of your desired rig is the same time that you notice that it’s two or three times what you can afford and, realistically, your shop floor experience with that stereo is the closest you’ll ever get to bringing hypersonic überbass slide-loading musiconica to your culinary experiences.

There are some pterosaur fossil specimens that seem similarly out of reach. They’re the ones that you see briefly when visiting museums, get sent a photograph of or see mentioned, briefly, in the literature. Should you make enquiries into their status, you’re very often told that someone else is researching them and, in true gentlemanly fashion, they’re to be left alone to pursue their studies to their conclusion. Other times, they’re just left alone because no-one is interested in them for the time being: this can be said of the ‘Painten Pelican’, a bizarre ctenochasmatoid on display in the Solnhofen Museum of Germany that appears to have something to do with Cycnorhamphus. It’s a seriously kick-ass, beautifully-preserved specimen of a gorgeous animal and I’d give my left arm to work on it, but until someone looks at it, it’s doing little else than sitting behind a glass panel. On occasion, interesting specimens are put up for sale online: recently, this shady process threw up a new Santana Formation pterosaur that, though Dave Martill pointed out to me that parts of this were fabricated, is almost certainly a new azhdarchoid taxon. One of the famous ‘KJ’ nyctosaurs (you know: the antler-crested ones described by Bennett [2003]) appeared on Ebay not too many weeks ago, too: both specimens, to my knowledge, have now disappeared off the radar completely. In all cases, these specimens are things that you can only pretend to play with at best: you can look at the pictures, infer what you can with very limited data and imagine what you could do with it should you be able to bring it home.

This brings us neatly to TMM 42489-2, or, as some of you may know it, the huge anterior skull and mandible fragment that Wellnhofer (1991) referred to Quetzalcoatlus on page 144 of his encyclopaedia (see image, above, drawn from the same photograph. Scale bar represents 100 mm). As we’ll see, it’s a dead exciting specimen but very little information about this specimen has been made public. It stems from the lower part of the Javelina Formation, the same Texan, latest Cretaceous sedimentological stomping ground as Quetzalcoatlus (Kellner 2004). It clearly belonged to a very large animal: although incomplete, the specimen is a good 800 mm long and around 350 mm tall: it’s entirely reasonable to think the entire skull was at least a metre in length when complete. Unlike many pterosaurs, it doesn’t bear a rostral headcrest but does bear a particularly expansive nasoantorbital fenestra. The rostrum itself is quite stubby and the upper jaw was quite deep, a condition that contrasts with the shallow lower jaw and the especially slender mandibular rami. Apparently, some cervical vertebrae (TMM 42489-1) were associated with this specimen, but little has been said of these other than that they were relatively shorter than those of Quetzalcoatlus (Kellner and Langston 1996). John Sibbick’s oft-copied reconstruction of Quetzalcoatlus in Wellnhofer (1991) took the morphology of TMM 42489-2 into account and gave his Quetz. a snub-nose. Thing is, the referral of TMM 4289-2 to Quetzalcoatlus is plain wrong: the skull material of Q. sp. was described by Kellner and Langston (1996) and while sharing the same generally crestless, pointy-tipped morphology, Q. sp. has a rostrum that is incredibly long – something like seven times longer than tall (see reconstruction of Q. sp, below, from Witton and Naish 2008. Scale bar represents 100 mm). Snub-nosed TMM 42489-2 is clearly not Quetzalcoatlus then, but we shouldn’t leave it there. Even the tiny experience we have with the specimen from Wellnhofer’s photograph shows that it must be something new for the Javelina Formation at least, but what is it?

Using the same photograph to form their opinions, several authors have had a stab at identifying TMM 42489-2. Everyone is happy that it represents an azhdarchoid: the combination of a large nasoantorbital fenestra and toothless jaws is not yet known from any other pterosaur group. Lű et al. (2006) noted similarities in the mandibular morphology and that of the azhdarchid Bakonydraco (Ősi et al. 2005), suggesting it would be represent a different type of Javelina azhdarchid. Slightly more exciting suggestsions were made by Kellner (2004), who suggested it was a late-surviving Tupuxuara-like tapejarid*. Martill and Naish (2006) agreed (in sorts), referring to it as the ‘Javelina Formation Tupuxuara’. These suggestions are potentially quite significant: latest Cretaceous pterosaur assemblages are almost entirely dominated by azhdarchids and, if TMM 42489-2 is a non-azhdarchid azhdarchoid, it means the end-Cretaceous pterosaur show was just a little richer than previously thought. It’s also noteworthy that, in recent years, another group of straight-jawed azhdarchoids, the chaoyangopterids, has been discovered (e.g. Lű et al. 2008) and may provide another potential taxonomic stable for the specimen: again, the existence of this group in the Late Cretaceous would be significant. Clearly, then, TMM 42489-2 could be of considerable importance for those trying to understand pterosaur evolutionary history, so what is it?

*The content of Tapejaridae is controversial with two broad schemes doing the rounds. Tapejaridae sensu Kellner (e.g. Kellner 2003, 2004; Kellner and Campos 2007) includes the short-faced, bent-jawed tapejarids (Tapejarinae) and bony sail crested forms Tupuxuara and Thalassodromeus (Thalassodrominae), whereas Tapejaridae sensu Unwin (e.g. Unwin 2003; Lű et al. 2008) is restricted to the short-faced, bent jawed forms. Tupuxuara and Thalassodromeus (forming Thalassodromidae – see Witton 2009) are grouped with other straight-jawed azhdarhchoids, chaoyangopterids and azhdarchids in Neoazhdarchia. This latter scheme is my preferred arrangement, but we don’t really have time to go into why here. That's not to say that we won't at a later date, though.

I looked into the affinities of TMM 42489-2 a little for my PhD when overhauling thalassodromid taxonomy (Witton 2008) but, unfortunately, found you can't really say much with absolute certainty: one image and brief descriptions of this specimen don’t really give much to work with. The mandible, in my view, is quite similar to most neoazhdarchian mandibles but not really identical to any. They’re all slender with shallow mandibular symphyses and, yes, while it does resemble that of Bakonydraco more than anything else, the Bakonydraco mandible doesn’t really look like the mandibles of other azhdarchids (e.g. Kellner and Langston 1996). Hence, this is only of limited use in figuring out exactly what TMM 42489-2 is. Likewise, the observation that the associated cervicals are shorter than those of Quetzalcoatlus doesn’t help much: Friday afternoon maths lessons were shorter than some azhdarchid vertebrae and, crucially, the longest and characteristically ‘azhdarchid’ vertebrae are only seen in the middle of the neck: proximal and distal vertebrae are comparatively stunted and complex (Pereda Suberbiola et al. 2003; Witton and Naish 2008). In this respect, they resemble the somewhat elongated cervical vertebrae of chaoyangopterids and, at the moment, I’m a little perplexed as to how to distinguish between the two: I wouldn’t be surprised if some azhdarchid occurrences represented solely by isolated cervicals are overturned once a way to distinguish the two groups are known. For the time being, though, it looks like the cervicals associated with TMM 42489-2 can provide little help on identifying the rostrum itself – and especially since there’s so little information available on them.

We are reliant, therefore, on rostral morphology alone to identify TMM 42489-2. Thankfully, there may be just enough data here to do the job. It appears that neoazhdarchians can be roughly diagnosed by attributes of their rostra when viewed in lateral profile through looking at the morphology and size ratio of the upper and lower bars encompassing the nasoantorbital fenesta (see image, above), the shape of the dorsal rostral margin and the slenderness of the rostrum itself (Martill and Naish 2006; Witton 2008). Thalassodromids have straight or convex dorsal rostral margins, comparatively tall upper premaxillary bars that extend posterodorsally in sub-parallel fashion and short, deep rostra; chaoyangopterids have very slender but also sub-parallel upper premaxillary bars, concave dorsal margins and short rostra, while azhdarchids have upper premaxillary bars that are much deeper than the lower distally but rapidly taper proximally, straight dorsal margins and extremely long rostra. TMM 42489-2 doesn’t meet any of these exactly but does come close: aside from the long rostrum, it’s ticks all the boxes for an azhdarchid rostrum with its straight dorsal margin and tapering upper premaxillary bar. While the rostral biometrics do undoubtedly resemble those of thalassodromids more than azhdarchids, it’s notable that the azhdarchid Bakonydraco has an usually short, wide mandible: the skull of this form is unknown, but, assuming it has a similar width/length ratio to the lower jaw, it should also have a short rostrum unless its skull morphology differs dramatically from those of other azhdarchoids. Likewise, the poorly-known but wide-skulled azhdarchid Hatzegopteryx presumably had a short rostrum or, if proportioned like better known azhdarchid skulls, would’ve had a most unwieldy 5 m long jaw (Buffetaut et al. 2002, 2003).

Based on the little evidence we have, then, TMM 42489-2 can be tentatively interpreted as a new type of snub-nosed azhdarchid. If this is correct, TMM 42489-2 may not be quite as exciting as when it was considered a late-surviving thalassodromid as proposed by Kellner (2004) or Martill and Naish (2006), but it does provide some enrichment of the uppermost Cretaceous pterosaur scene by demonstrating significant morphological variation between azhdarchids. The differences in snout morphology will have some implications on feeding habits and dietary preferences, and these hints of ecological differentiation may explain how azhdarchids managed to be so abundant and successful. Plus, it’s made that little more exciting by being quite big - a 5 m wingspan seems quite reasonable for an azhdrchid with a 1 m long skull - and it almost certainly represents a new taxon, being readily distinguished from all other toothless pterosaurs through the shape of its rostrum. Can we do anything about all this, though? Can we heck: until the specimen is properly described and figured, it would be foolish to make it the focus of any study or attach a name to it. Until someone studies TMM 42489-2 properly then, it remains the pterosaur equivalent of an electronic store demonstration model: full of buzz, promise and excitement, but something that you can't really do anything with until you're ready to make the investment. Or someone else invests in it for you, which would be great.

Witton, M. P. 2009. A new species of Tupuxuara (Thalassodromidae, Azhdarchoidea) from the Lower Cretaceous Santana Formation of Brazil, with a note on the nomenclature of Thalassodromidae. Cretaceous Research, 30, 1293-1300.

Monday, February 8, 2010

UPDATE: 25/02/10. A while back, we posted an early version of the second circular for the 2010 Flugsaurier Meeting but, almost immediately, were told that a modified version would follow soon after. 'Soon after' means today, and what follows is the corrected version. The most important details - price, dates and deadlines - remain unchanged, but a few minor tweaks have been made here and there.

While the Pterosaur.net blog obviously is primarily set to cater for those with an interest in pterosaurs, rather than those dedicated to pterosaur research, it would be remiss to leave this out on the blog. There have been a number of pterosaur-dedicated meetings or seminars within meetings over the years, but only recently has this become more formal with a planned series or regular meetings devoted entirely to pterosaurs. The next scheduled one is however this summer in Beijing, and just out (literally, as of less than half an hour ago) is the second circular with all the details needed to sign up and attend.

This is of course a scientific meeting so don't think about coming unless you want to be immersed in the anatomical and systematic minutae of pterosaurs and lots of very techie details and arguments. If that is your bag however, all are of course welcome.

I’m sure I’ll see at least a few of you there. I have left out some details of the registration and payment methods etc. contact JC or Dave Unwin (or me I suppose, since I have a copy of the forms) for details. Everything else you need is below:

Pterosaurs are amongst the most fascinating and enigmatic of all extinct creatures. Thanks to some spectacular fossil finds in recent years our understanding of the palaeobiology and evolutionary history of these ‘flying reptiles’ has seen several dramatic advances. Some of the most important discoveries, including the first eggs with embryos, have been made in China where Late Jurassic/Early Cretaceous rocks are currently producing new species of pterosaurs at a faster rate than anywhere else in the world. In recognition of this, the Third International Symposium on Pterosaurs “Flugsaurier 2010” will be held in China in August 2010. This will be the third international pterosaur symposium and follows successful meetings held in France in 2001 and Germany in 2007.

The meeting will be organized mainly by the China Geological Survey, sponsored by the Institute of Geology, Chinese Academy of Geological Sciences, and co-sponsored by:China Fossil Preservation Foundation,China Dinosaur Park of Changzhou,The Bureau of Fossil Protection, Liaoning Provincial Department of National Land Resources, The Government of Beipiao City.

The meeting is planned for the 5th-10th August, 2010. Talks, posters, at least one open discussion session and (subject to availability) examination of specimens are planned for the first three days of the meeting. This will be followed by an optional three day field excursion to view exposures of the Jehol Group and exhibitions/collections of fossils from this sequence which has yielded more than 100 specimens of pterosaurs in the last 10 years. All those interested in pterosaurs and the communities and environments in which they lived are encouraged to attend.

1. Meeting aims:

As in previous symposia, this meeting is intended to cover all aspects of pterosaur palaeobiology and the world in which they live, including:(a) The origin and evolution of pterosaurs(b) Taxonomy, systematics and phylogeny(c) Palaeobiology including anatomy, functional morphology and ontogeny(d) Taphonomy, sedimentology and preservational environments(e) Ecosystems and contemporaneous fauna and flora

Oral presentations will consist of key-note lectures (45 minutes) and talks (30 minutes). These times include at least 5 minutes for questions and discussion. Attendees can apply to deliver more than one talk and /or poster.

Posters: There will be at least one poster session (Posters should be prepared so that they fit onto a board with maximum dimensions of 90 cm (height) X 120 cm (width).

3. Abstracts and Symposium Volumes

An abstract volume will be prepared for distribution at the meeting. The abstract submission deadline is March 31st, 2010. No abstracts will be accepted after this date. Abstracts of up to two printed pages (A4; all text: Arial; title: 14pt, all caps; authors: 14pt, bold; address: 12 pt, italics; text: 12 pt, single spaced) including figures and references if desired are preferred, but longer abstracts will be considered. Preferred formats are “Word” for text files and “JPG” for figures. A symposium volume is planned for publication in 2011 and will be open to both attendees and non-attendees, with preference given to the former. The deadline for manuscript submissions will be December 31st, 2010.

4. Registration

Registration fee is $450 US for professional participants, $200 US for students and accompanying persons. The registration fee covers all the costs of the meeting: registration, the fieldtrip, accommodation for the duration of the meeting (including the fieldtrip) and all meals.

Please send payment to (Before the end of June)：Institute of Geology, Chinese Academy of Geological SciencesBank name: BAIWANZHUANG SUBBRANCH, INDUSTRIAL AND COMMERCIAL BANK OF CHINAACCOUNT No. 0200001409008818443ADDRESS: No.26 BAIWANZHUANG ROAD, XICHENG DISTRICT, BEIJING 100037, CHINA.Tel.: 008610-68999665Please note:Payment of fees at the registration desk can be done by cash (US dollars or Chinese yuan). Credit cards and cheques can not be accepted. All refunds (including non-attendance) will incur a 25% charge. We will arrange accommodation for all attendees. If you have any questions regarding accommodation, or would prefer to organize your own accommodation please contact us immediately.

Tuesday, February 2, 2010

Way back in 2008, I was working on a skeletal reconstruction of Pteranodon longiceps, sourced mostly from Chris Bennett's (1991) dissertation. It included a dorsal and a lateral view, and all I had left to do were the feet (feet are fiddly, annoying, and somewhat boring). While I was procrastinating about the feet, Mike Hanson beat me to the punch, and produced a skeletal reconstruction based on the same source. It wasn't just that he got there first, but it was better than mine to boot, with more views, and a more carefully drawn skull. So I gave up, and left my still footless Pteranodon to go mouldy on my hard drive.

A couple of weeks ago, I decided to revisit my Pteranodon skeletal, to see if it was in a fit state to be incorporated into a new project. I also wanted to include the suggestion made by Claessens et al (2009) that the sternum sloped ventrally, rather than dorsally or flat and usually shown. As I started tweaking things, especially as I was working on an anterior view, I realised there was something quite wrong with my Pteranodon… the scapulocoracoid, when drawn in anterior view, was dorsoventrally way too short. I couldn’t get the coracoid to articulate with the sternum, not by a long shot.

My drawing matched Bennett’s (1991), Hanson’s (2008), Claessens et al (2009), and other drawings pretty well. So, if mine was wrong, then there was something wrong with a lot of the Pteranodon reconstructions out there.

Moving the sternum up posed something of a problem, however, because the ribs didn’t seem to fit. Looking into this more closely, it appears Bennett’s drawings show the ribs flattened toward the viewer. In other words, there is little accounting for curvature and foreshortening, which has the effect of making the ribcage far too deep.

Comparing different people's drawings, something quite interesting emerged, Pteranodon is nearly always reconstructed with a teardrop shaped trunk. Bennett’s original 1991 drawing and Hanson’s closely related 2008 drawing both have the error of an overly deep ribcage and scapulocoracoid. They also have the sternum sloping dorsally. These things combined give a strong teardrop shape. Greg Paul’s (2002) drawing has a similar shape, but it achieves this in a completely different way.* Paul seems to have the depth of the ribcage and scapulocoracoid right, and even has a gentle ventral slope to the sternum, but he also adds a deep keel to the sternum, which I presume is meant to be cartilaginous (it isn’t preserved in pterosaurs I’ve seen). So again, a classic teardrop shape. Claessens et al (2009) has a more pronounced ventral slope to the sternum, but it also has the overly deep ribs and scapulocoracoid; which makes for a slightly more portly teardrop.

If we combine a (keel-less) ventrally sloping sternum, and make the ribcage and scapulocoracoid shallower as I think they ought to be, we end up with a different sort of shape for Pteranodon's trunk. A distinctly pot-bellied one:

Sloping the sternum ventrally would make most pterosaurs deeper in the mid-trunk than we are used to drawing them, so I am looking forward to seeing whether other pterosaurs will turn out to be so hilariously shaped.

Monday, February 1, 2010

If 'gently piping' music means 'loud enough that you can't talk to your housemate several rooms away from the stereo', then this evening I was gently piping Portished's Third throughout my, and probably my neighbours, house. If you've not heard it, I recommend you immediately travel to your local music shop or favourite download site and grab a copy: it's great. In fact, if we lived in the same alternate reality that spawned the Flight of the Conchords track Mother Uckers, I'd say it was totally ucking brilliant. It's the sort of music that, using distorted electronic tones and unsettling beats to make sure you're paying attention, fills your ears with delicate, haunted tracks at times or, at others, makes you feel like you're marching into a war where Vangelishas provided the soundtrack. If intelligent, arresting and intense musical experience is what you're after, I can't rate it highly enough.

If you're not after something intelligent, arresting or intense, however, you could do much worse than check out my interview responses to questions asked and posted by David Orr, owner of Love in the Time of Chasmosaurus. LITCprovides daily palaeo-themed posts on all manner of topics, ranging from news on recent discoveries, looks at butt-ugly roadside dinosaur models, palaeo-themed toys and, most importantly, the first episode of Dino Riders. I can honestly say I check it every day as part of my morning procrastination routine at work and consistently find it a sharp, punchy read. Much of the blog is devoted to vintage palaeoart and if, like me, you grew up reading dinosaur books, I guarantee you'll find waves of forgotten memories flooding back if you scroll through the LITCarchives. There're also occasional interviews with palaeoartists - including real professionals like John Sibbick- and, a few weeks ago, David very flatteringly asked me if I'd be interested in answering a few questions. A good portion of the discussion concerned pterosaurs and, for those interested, you can find the interview, in its entirety, here.

The image above, incidentally, has nothing in particular to do with anything you've just read, but makes the post look nicer. It shows a profile of the large, snubbed-jawed ornithocheiridColoborhynchus, commissioned as part of a series of pterosaur mug-sketches to show the diversity of their cranial morphology. Hopefully, the full complement of sketches will be published later this year.